Here are some examples:
* Metamorphosis: A change in form or structure, especially a striking one.
* Metacognition: Thinking about thinking.
* Metaphysics: The study of the fundamental nature of reality.
The prefix meaning behind is retro-.
Here are some examples:
* Retrospective: Looking back on the past.
* Retroactive: Applying to a period prior to enactment.
* Retrograde: Moving backward or declining.